IB/uverbs: Support for query QP from userspace

Add support to uverbs to handle querying userspace QPs (queue pairs),
including adding an ABI for marshalling requests and responses.  The
kernel midlayer already has the underlying ib_query_qp() function.
Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/uverbs.h

@@ -183,6 +183,7 @@ IB_UVERBS_DECLARE_CMD(poll_cq);
 IB_UVERBS_DECLARE_CMD(req_notify_cq);
 IB_UVERBS_DECLARE_CMD(destroy_cq);
 IB_UVERBS_DECLARE_CMD(create_qp);
+IB_UVERBS_DECLARE_CMD(query_qp);
 IB_UVERBS_DECLARE_CMD(modify_qp);
 IB_UVERBS_DECLARE_CMD(destroy_qp);
 IB_UVERBS_DECLARE_CMD(post_send);

drivers/infiniband/core/uverbs_cmd.c

@@ -996,6 +996,106 @@ ssize_t ib_uverbs_create_qp(struct ib_uverbs_file *file,
 	return ret;
 }
 
+ssize_t ib_uverbs_query_qp(struct ib_uverbs_file *file,
+			   const char __user *buf, int in_len,
+			   int out_len)
+{
+	struct ib_uverbs_query_qp      cmd;
+	struct ib_uverbs_query_qp_resp resp;
+	struct ib_qp                   *qp;
+	struct ib_qp_attr              *attr;
+	struct ib_qp_init_attr         *init_attr;
+	int                            ret;
+
+	if (copy_from_user(&cmd, buf, sizeof cmd))
+		return -EFAULT;
+
+	attr      = kmalloc(sizeof *attr, GFP_KERNEL);
+	init_attr = kmalloc(sizeof *init_attr, GFP_KERNEL);
+	if (!attr || !init_attr) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	mutex_lock(&ib_uverbs_idr_mutex);
+
+	qp = idr_find(&ib_uverbs_qp_idr, cmd.qp_handle);
+	if (qp && qp->uobject->context == file->ucontext)
+		ret = ib_query_qp(qp, attr, cmd.attr_mask, init_attr);
+	else
+		ret = -EINVAL;
+
+	mutex_unlock(&ib_uverbs_idr_mutex);
+
+	if (ret)
+		goto out;
+
+	memset(&resp, 0, sizeof resp);
+
+	resp.qp_state               = attr->qp_state;
+	resp.cur_qp_state           = attr->cur_qp_state;
+	resp.path_mtu               = attr->path_mtu;
+	resp.path_mig_state         = attr->path_mig_state;
+	resp.qkey                   = attr->qkey;
+	resp.rq_psn                 = attr->rq_psn;
+	resp.sq_psn                 = attr->sq_psn;
+	resp.dest_qp_num            = attr->dest_qp_num;
+	resp.qp_access_flags        = attr->qp_access_flags;
+	resp.pkey_index             = attr->pkey_index;
+	resp.alt_pkey_index         = attr->alt_pkey_index;
+	resp.en_sqd_async_notify    = attr->en_sqd_async_notify;
+	resp.max_rd_atomic          = attr->max_rd_atomic;
+	resp.max_dest_rd_atomic     = attr->max_dest_rd_atomic;
+	resp.min_rnr_timer          = attr->min_rnr_timer;
+	resp.port_num               = attr->port_num;
+	resp.timeout                = attr->timeout;
+	resp.retry_cnt              = attr->retry_cnt;
+	resp.rnr_retry              = attr->rnr_retry;
+	resp.alt_port_num           = attr->alt_port_num;
+	resp.alt_timeout            = attr->alt_timeout;
+
+	memcpy(resp.dest.dgid, attr->ah_attr.grh.dgid.raw, 16);
+	resp.dest.flow_label        = attr->ah_attr.grh.flow_label;
+	resp.dest.sgid_index        = attr->ah_attr.grh.sgid_index;
+	resp.dest.hop_limit         = attr->ah_attr.grh.hop_limit;
+	resp.dest.traffic_class     = attr->ah_attr.grh.traffic_class;
+	resp.dest.dlid              = attr->ah_attr.dlid;
+	resp.dest.sl                = attr->ah_attr.sl;
+	resp.dest.src_path_bits     = attr->ah_attr.src_path_bits;
+	resp.dest.static_rate       = attr->ah_attr.static_rate;
+	resp.dest.is_global         = !!(attr->ah_attr.ah_flags & IB_AH_GRH);
+	resp.dest.port_num          = attr->ah_attr.port_num;
+
+	memcpy(resp.alt_dest.dgid, attr->alt_ah_attr.grh.dgid.raw, 16);
+	resp.alt_dest.flow_label    = attr->alt_ah_attr.grh.flow_label;
+	resp.alt_dest.sgid_index    = attr->alt_ah_attr.grh.sgid_index;
+	resp.alt_dest.hop_limit     = attr->alt_ah_attr.grh.hop_limit;
+	resp.alt_dest.traffic_class = attr->alt_ah_attr.grh.traffic_class;
+	resp.alt_dest.dlid          = attr->alt_ah_attr.dlid;
+	resp.alt_dest.sl            = attr->alt_ah_attr.sl;
+	resp.alt_dest.src_path_bits = attr->alt_ah_attr.src_path_bits;
+	resp.alt_dest.static_rate   = attr->alt_ah_attr.static_rate;
+	resp.alt_dest.is_global     = !!(attr->alt_ah_attr.ah_flags & IB_AH_GRH);
+	resp.alt_dest.port_num      = attr->alt_ah_attr.port_num;
+
+	resp.max_send_wr            = init_attr->cap.max_send_wr;
+	resp.max_recv_wr            = init_attr->cap.max_recv_wr;
+	resp.max_send_sge           = init_attr->cap.max_send_sge;
+	resp.max_recv_sge           = init_attr->cap.max_recv_sge;
+	resp.max_inline_data        = init_attr->cap.max_inline_data;
+	resp.sq_sig_all             = !!init_attr->sq_sig_type;
+
+	if (copy_to_user((void __user *) (unsigned long) cmd.response,
+			 &resp, sizeof resp))
+		ret = -EFAULT;
+
+out:
+	kfree(attr);
+	kfree(init_attr);
+
+	return ret ? ret : in_len;
+}
+
 ssize_t ib_uverbs_modify_qp(struct ib_uverbs_file *file,
 			    const char __user *buf, int in_len,
 			    int out_len)

drivers/infiniband/core/uverbs_main.c

@@ -96,6 +96,7 @@ static ssize_t (*uverbs_cmd_table[])(struct ib_uverbs_file *file,
 	[IB_USER_VERBS_CMD_REQ_NOTIFY_CQ]     	= ib_uverbs_req_notify_cq,
 	[IB_USER_VERBS_CMD_DESTROY_CQ]    	= ib_uverbs_destroy_cq,
 	[IB_USER_VERBS_CMD_CREATE_QP]     	= ib_uverbs_create_qp,
+	[IB_USER_VERBS_CMD_QUERY_QP]     	= ib_uverbs_query_qp,
 	[IB_USER_VERBS_CMD_MODIFY_QP]     	= ib_uverbs_modify_qp,
 	[IB_USER_VERBS_CMD_DESTROY_QP]    	= ib_uverbs_destroy_qp,
 	[IB_USER_VERBS_CMD_POST_SEND]    	= ib_uverbs_post_send,

include/rdma/ib_user_verbs.h

@@ -370,6 +370,47 @@ struct ib_uverbs_qp_dest {
 	__u8  port_num;
 };
 
+struct ib_uverbs_query_qp {
+	__u64 response;
+	__u32 qp_handle;
+	__u32 attr_mask;
+	__u64 driver_data[0];
+};
+
+struct ib_uverbs_query_qp_resp {
+	struct ib_uverbs_qp_dest dest;
+	struct ib_uverbs_qp_dest alt_dest;
+	__u32 max_send_wr;
+	__u32 max_recv_wr;
+	__u32 max_send_sge;
+	__u32 max_recv_sge;
+	__u32 max_inline_data;
+	__u32 qkey;
+	__u32 rq_psn;
+	__u32 sq_psn;
+	__u32 dest_qp_num;
+	__u32 qp_access_flags;
+	__u16 pkey_index;
+	__u16 alt_pkey_index;
+	__u8  qp_state;
+	__u8  cur_qp_state;
+	__u8  path_mtu;
+	__u8  path_mig_state;
+	__u8  en_sqd_async_notify;
+	__u8  max_rd_atomic;
+	__u8  max_dest_rd_atomic;
+	__u8  min_rnr_timer;
+	__u8  port_num;
+	__u8  timeout;
+	__u8  retry_cnt;
+	__u8  rnr_retry;
+	__u8  alt_port_num;
+	__u8  alt_timeout;
+	__u8  sq_sig_all;
+	__u8  reserved[5];
+	__u64 driver_data[0];
+};
+
 struct ib_uverbs_modify_qp {
 	struct ib_uverbs_qp_dest dest;
 	struct ib_uverbs_qp_dest alt_dest;